A conventional door glass of an automobile may be opened and closed by sliding along a sliding rail upwardly and downwardly. In this technology, it is required that the shape of the vehicle door is adapted to the partitioned shape of a sliding glass and it is also required that the vehicle door has enough sliding space. A big enough sliding glass may be partitioned from the conventional shape of the vehicle door. When the glass slides downwardly along the sliding rail into the lower portion of the door, there is enough space between the inner and outer plates of the vehicle door to receive the glass.
A vehicle door for a recreational vehicle made by the present applicant is significantly different from the conventional vehicle door. In terms of the shape, such vehicle door is of an irregular circular shape, so a big enough glass cannot be partitioned from the door if the common technical solution in which the glass is slid upwardly and downwardly is adopted. Additionally, in terms of the shape, a straight edge is obliquely disposed between the upper half part and the lower half part of the vehicle door, and due to the small thickness of the vehicle door, the space between the inner and outer plates of the lower half part of the vehicle door is very small, so it is very difficult to arrange a existing glass lifting mechanism therein. Therefore, the existing technical solution of lifting glass of the vehicle door cannot solve the problem of opening and closing the glass of the vehicle door with the irregular-circular frame for the recreational vehicle.